Colchicine solid complex; methods of making; and methods of use thereof

ABSTRACT

Disclosed are new colchicine solid complexes, methods of making the solid complexes as well as formulation prepared therefrom and uses thereof.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 61/042,897 filed Apr. 7, 2008, which is hereby incorporated byreference in its entirety.

BACKGROUND

Colchicine, chemical name(−)-N-[(7S,12aS)-1,2,3,10-tetramethoxy-9-oxo-5,6,7,9-tetrahydrobenzo[a]heptalen-7-yl]-acetamide,(N-((7S)-5,6,7,9-tetrahydro-1,2,3,10-tetramethoxy-9-oxobenzo[a]heptalen-7-yl)-acetamide,IUPAC), CAS Registry No. 64-86-8 is a known gout suppressant.

Different crystalline forms, non-crystalline forms, hydrates andsolvates of an active agent can exhibit vastly different physicalproperties such as solubility, melting point, hardness, opticalproperties, dissolution, and the like. These differences such as varyingdissolution can result in differences in the therapeutic activity. Athorough understanding of the various crystalline forms, non-crystallineforms, hydrates and solvates of an active agent is an importantconsideration in formulating the active agent, specifically when tryingto achieve consistency of any resulting pharmaceutical product batch tobatch.

There remains a need in the art for new solid forms of colchicine havingimproved properties of solubility, stability, processability and thelike.

SUMMARY

In one embodiment, a solid complex comprises colchicine and a guest,wherein the guest is malic acid, oxalic acid, or para-toluenesulfonicacid.

In another embodiment, a composition comprises a solid complexcomprising colchicine and a guest, wherein the guest is malic acid,oxalic acid or para-toluenesulfonic acid; and a pharmaceuticallyacceptable excipient.

In yet another embodiment, a method of preparing a solid complexcomprises slurrying a combination of colchicine, L-malic acid, and ethylacetate to form colchicine malic acid co-crystal.

In still yet another embodiment, a method of preparing a solid complexcomprises preparing colchicine malic acid co-crystal by vapor diffusionof hexanes into an ethyl acetate solution containing equimolar amountsof colchicine and L-malic acid.

In yet another embodiment, a method of preparing a solid complexcomprises crystallizing colchicine oxalic acid co-crystal from asolution of acetonitrile and diethyl ether.

In one embodiment, a method of preparing a solid complex comprisescrystallizing colchicine para-toluenesulfonic acid co-crystal from asolution of tetrahydrofuran and hexanes.

These and other embodiments, advantages and features of the presentinvention become clear when detailed description and examples areprovided in subsequent sections.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an XRPD pattern of colchicine malic acid co-crystal.

FIG. 2 illustrates a FT-Raman spectrum of colchicine malic acidco-crystal.

FIG. 3 illustrates an XRPD pattern of colchicine oxalic acid co-crystal.

FIG. 4 illustrates a FT-Raman spectrum of colchicine oxalic acidco-crystal.

FIG. 5 illustrates an XRPD pattern of colchicine oxalic acid co-crystal,tetrahydrofuran solvate.

FIG. 6 illustrates an XRPD pattern of colchicine para-toluenesulfonicacid co-crystal.

FIG. 7 illustrates a FT-Raman spectrum of colchicinepara-toluenesulfonic acid co-crystal.

DETAILED DESCRIPTION

Disclosed herein are novel colchicine solid complexes, methods ofpreparing the solid complexes, compositions prepared therefrom, and usesthereof. It has been unexpectedly discovered herein that colchicine canexists as a solid complex (e.g., a co-crystal) with different guestmolecules. Novel solid complexes disclosed herein include colchicinemalic acid co-crystal, colchicine oxalic acid co-crystal, colchicineoxalic acid co-crystal tetrahydro furan solvate, and colchicinepara-toluenesulfonic acid co-crystal.

“Solid complex” means a solid form containing colchicine and anadditional component (“guest”) which interact with one another to resultin a solid material having a different physicochemical property than thecorresponding free colchicine. The interactions between the colchicineand the guest can be hydrogen bonding, van der Waals interactions,electrostatic interactions, hydrophobic interactions, ionicinteractions, a combination thereof, and the like. Exemplary solidcomplexes include co-crystals (i.e. a crystalline supramolecularcomplex), single phase molecular dispersions, and the like. Theproperties can include solubility, melting point, spectroscopic, etc.

The solid complex may include one or more solvate or water molecules inthe crystalline lattice (e.g., solvates or hydrates of co-crystals, or aco-crystal further comprising a solvent or water molecule).

“Colchicine” is inclusive of all crystalline forms including allpolymorphs, non-crystalline forms, anhydrous forms, hydrates, andsolvates unless specifically indicated otherwise.

“Guest” means an organic acid, specifically malic acid, oxalic acid, andpara-toluenesulfonic acid.

The ratio of colchicine to guest may be for example, 1:1, 1:1.5, and1:2. In certain embodiments, the ratio is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6,1:7, 1:8, 1:9, or 1:10 colchicine to guest. In other embodiments, theratio is 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10 guest tocolchicine.

The solid complexes can be physically distinguished from crystallinecolchicine using a variety of analytical tools and characterizationmethods, such as, for example, Raman spectroscopy, IR spectroscopy (IR,FT-IR), X-ray powder diffraction (XRPD) crystallography, X-raycrystallography, neutron diffraction, Synchrotron radiation, solid state¹H-NMR spectroscopy, differential scanning calorimetry (DSC),Thermogravimetric analysis (TGA), Thermogravimetric/infrared analysis(TG-IR), melting point, and heats of fusion.

The colchicine solid complexes can be prepared using a variety ofmethods including crystallization, antisolvent precipitation, slowcooling of a solution of colchicine and guest, precipitation from asolution of colchicine and guest at a constant temperature (e.g., aboutroom temperature, about 1.0 to about 4.0° C., about 0° C.), seedingsolutions of colchicine and guest with optional cooling, slurrying,vapor diffusion, and the like.

Vapor diffusion process involves preparation of solutions of colchicineand a guest in a solvent system at ambient temperature. The solutionsare placed into an open container and the container is placed in asealed chamber containing an anti-solvent. The anti-solvent is misciblewith the solvent system. The chamber is left undisturbed until solidformation occurs.

In one embodiment, a method of preparing colchicine malic acidco-crystal is by vapor diffusion of hexanes into an ethyl acetatesolution containing equimolar amounts of colchicine and L-malic acid.

The solvent process generally involves preparing a solution orsuspension of colchicine and guest in a solvent system followed byoptional removal of the solvent. In the solution process, bothcolchicine and guest are completely dissolved in the solvent system,wherein in the suspension process, the colchicine or guest can remainpartially undissolved.

“Solvent system” means a single or a combination of two or moresolvents.

Suitable solvents for preparing the colchicine solid complex includethose that do not adversely affect the stability of the colchicine,guest or solid complex, and are preferably inert. Suitable solvents maybe organic, aqueous, or a mixture thereof. Suitable organic solvents maybe aliphatic alcohols such as methanol (MeOH), ethanol (EtOH),n-propanol, isopropanol (IPA), n-butanol, tert-amyl alcohol (t-AmOH),tert-butyl alcohol, trifluoroethanol, and 2-ethoxyethanol, particularlylower alkyl (C₁-C₆) alcohols; ethers such as diethyl ether,tetrahydrofuran (THF), dioxane, methyl-tert-butyl ether,1,2-dimethoxyethane (DME), and 2-methyl tetrahydrofuran; aliphaticketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutylketone; aliphatic carboxylic esters such as methyl acetate, ethylacetate (EtOAc), and isopropyl acetate; aromatic hydrocarbons such asbenzene, toluene, and xylene; aliphatic hydrocarbons such as hexanes;aliphatic nitriles such as acetonitrile (MeCN) and propionitrile;chlorinated hydrocarbons such as dichloromethane (DCM), chloroform, andcarbon tetrachloride; aliphatic sulfoxides such as dimethyl sulfoxide(DMSO); amides such as dimethylformamide (DMF) and dimethylacetamide(DMA); organic acids such as acetic acid; N-methyl-2-pyrrolidone;pyridine; and the like, as well as mixtures comprising at least one ofthe foregoing organic solvents. Certain solvents can be used as ananti-solvent to induce crystal formation from solution.

Optionally, the solution, prior to any solids formation, can be filteredto remove any undissolved solids, solid impurities and the like prior tosolid complex formation. Any filtration system and filtration techniquesknown in the art can be used.

In one embodiment, the solutions or suspensions can be seeded with thedesired colchicine solid complex.

In one embodiment, the solutions or suspensions can be sonicated.

In one embodiment, a method of preparing colchicine oxalic acidco-crystal comprises crystallizing the co-crystal from a solution ofacetonitrile and diethyl ether.

In another embodiment, a method of preparing colchicinepara-toluenesulfonic acid co-crystal comprises crystallizing theco-crystal from a solution of tetrahydrofuran and hexanes.

In yet another embodiment, a method of preparing colchicine malic acidco-crystal comprises slurrying a combination of colchicine, L-malicacid, and ethyl acetate to form colchicine malic acid co-crystal.

In one embodiment, the solvent system of the solution or suspension ofcolchicine, guest, and solvent system is removed slowly or rapidly.Rapid removal of the solvent system can be achieved in less than aminute by processes such as spray drying. Slow removal of the solventsystem can be achieved in a minute or greater using methods such asevaporation under reduced pressure or evaporation at atmosphericpressure. Removal of the solvent system can be achieved with optionalheating.

In one embodiment, a colchicine malic acid solid complex is a co-crystalexhibiting XRPD peak positions at 6.0, 7.2, 8.5, 11.1, 13.1, 16.3, 16.7,18.4, 19.9, 22.0, and 24.6±0.2 degrees 2-theta. In another embodiment, acolchicine malic acid solid complex is a co-crystal exhibiting the XRPDpeak positions as in Table 1 below. In yet another embodiment, acolchicine malic acid solid complex is a co-crystal exhibiting an XRPDpattern which is substantially similar to FIG. 1. In another embodiment,a colchicine malic acid solid complex is a co-crystal exhibitingFT-Raman peaks at 2935, 1595, 1500, 1444, 1350, 1324, and 1287±4 cm⁻¹.In another embodiment, a colchicine malic acid solid complex is aco-crystal exhibiting FT-Raman peaks as in Table 3 below. In yet anotherembodiment, a colchicine malic acid solid complex is a co-crystalexhibiting a FT-Raman spectrum which is substantially similar to FIG. 2.In one embodiment, a colchicine malic acid solid complex is a co-crystalexhibiting an endotherm peak of about 70° C. by differential scanningcalorimetry analysis. In one embodiment, a colchicine malic acid solidcomplex is a colchicine malic acid co-crystal having a ratio of about1:1 malic acid:colchicine.

In one embodiment, a colchicine oxalic acid solid complex is aco-crystal exhibiting XRPD peak positions at 7.4, 9.2, 9.4, 10.8, 12.0,12.3, 14.4, 15.9, 17.8, 18.9, 20.5, and 23.7±0.2 degrees 2-theta. Inanother embodiment, a colchicine oxalic acid solid complex is aco-crystal exhibiting the XRPD peak positions as in Table 4 below. Inyet another embodiment, a colchicine oxalic acid solid complex is aco-crystal exhibiting an XRPD pattern which is substantially similar toFIG. 3. In another embodiment, a colchicine oxalic acid solid complex isa co-crystal exhibiting FT-Raman peaks at 2934, 1592, 1549, 1505, 1436,and 1401±4 cm⁻¹. In another embodiment, a colchicine oxalic acid solidcomplex is a co-crystal exhibiting FT-Raman peaks as in Table 6 below.In yet another embodiment, a colchicine oxalic acid solid complex is aco-crystal exhibiting a FT-Raman spectrum which is substantially similarto FIG. 4. In one embodiment, a colchicine oxalic acid solid complex isa co-crystal exhibiting an endotherm peak of about 144° C. bydifferential scanning calorimetry analysis. In one embodiment, acolchicine oxalic acid solid complex is a colchicine oxalic acidco-crystal having a ratio of about 1:2 oxalic acid:colchicine.

In another embodiment, a colchicine oxalic acid solid complex is acolchicine oxalic acid co-crystal, tetrahydrofuran solvate exhibiting anXRPD pattern which is substantially similar to FIG. 5. In oneembodiment, a colchicine oxalic acid solid complex is a colchicineoxalic acid co-crystal, tetrahydrofuran solvate having a ratio of about1:2:1 oxalic acid:colchicine:tetrahydro furan.

In one embodiment, a colchicine para-toluenesulfonic acid solid complexis a co-crystal exhibiting XRPD peak positions at 6.6, 6.8, 9.6, 12.8,14.3, 15.1, 17.1, 18.6, and 22.7±0.2 degrees 2-theta. In anotherembodiment, a colchicine para-toluenesulfonic acid solid complex is aco-crystal exhibiting the XRPD peak positions as in Table 8 below. Inyet another embodiment, a colchicine para-toluenesulfonic acid solidcomplex is a co-crystal exhibiting an XRPD pattern which issubstantially similar to FIG. 6. In another embodiment, a colchicinepara-toluenesulfonic acid solid complex is a co-crystal exhibitingFT-Raman peaks at 1516, 1468, and 1322±4 cm⁻¹. In another embodiment, acolchicine para-toluenesulfonic acid solid complex is a co-crystalexhibiting FT-Raman peaks as in Table 10 below. In yet anotherembodiment, a colchicine para-toluenesulfonic acid solid complex is aco-crystal exhibiting a FT-Raman spectrum which is substantially similarto FIG. 7. In one embodiment, a colchicine para-toluenesulfonic acidsolid complex is a co-crystal exhibiting an endotherm peak of about 198°C. by differential scanning calorimetry analysis. In one embodiment, acolchicine para-toluenesulfonic acid solid complex is a colchicinepara-toluenesulfonic acid co-crystal having a ratio of about 1:1para-toluenesulfonic acid:colchicine.

Also disclosed are pharmaceutical compositions comprising the colchicinesolid complexes prepared herein.

Solid dosage forms for oral administration include, but are not limitedto, capsules, tablets, powders, and granules. In such solid dosageforms, the solid complex may be admixed with one or more of thefollowing: (a) one or more inert excipients (or carriers), such assodium citrate or dicalcium phosphate; (b) fillers or extenders, such asstarches, lactose, sucrose, glucose, mannitol, and silicic acid; (c)binders, such as carboxymethylcellulose, alignates, gelatin,polyvinylpyrrolidone, sucrose, and acacia; (d) humectants, such asglycerol; (e) disintegrating agents, such as agar-agar, calciumcarbonate, potato or tapioca starch, alginic acid, certain complexsilicates, and sodium carbonate; (f) solution retarders, such asparaffin; (g) absorption accelerators, such as quaternary ammoniumcompounds; (h) wetting agents, such as cetyl alcohol and glycerolmonostearate; (i) adsorbents, such as kaolin and bentonite; and (j)lubricants, such as talc, calcium stearate, magnesium stearate, solidpolyethylene glycols, sodium lauryl sulfate, and combinations comprisingone or more of the foregoing additives. For capsules and tablets, thedosage forms may also comprise buffering agents.

By “oral dosage form” is meant to include a unit dosage form for oraladministration. An oral dosage form may optionally comprise a pluralityof subunits such as, for example, microcapsules or microtablets.Multiple subunits may be packaged for administration in a single dose.

By “subunit” is meant to include a composition, mixture, particle,pellet, etc., that can provide an oral dosage form alone or whencombined with other subunits.

The compositions can be immediate-release forms or controlled-releaseforms.

By “immediate-release” is meant a conventional or non-modified releasein which greater then or equal to about 75% of the active agent isreleased within two hours of administration, specifically within onehour of administration.

By “controlled-release” is meant a dosage form in which the release ofthe active agent is controlled or modified over a period of time.Controlled can mean, for example, sustained-, delayed- or pulsed-releaseat a particular time. Alternatively, controlled can mean that therelease of the active agent is extended for longer than it would be inan immediate-release dosage form, e.g., at least over several hours.

Dosage forms can be combination dosage forms having bothimmediate-release and controlled-release characteristics, for example, acombination of immediate-release pellets and controlled-release pellets.The immediate-release portion of a combination dosage form may bereferred to as a loading dose.

Certain compositions described herein may be “coated”. The coating maybe a suitable coating, such as, a functional or a non-functionalcoating, or multiple functional or non-functional coatings. By“functional coating” is meant to include a coating that modifies therelease properties of the total composition, for example, asustained-release coating. By “non-functional coating” is meant toinclude a coating that is not a functional coating, for example, acosmetic coating. A non-functional coating can have some impact on therelease of the active agent due to the initial dissolution, hydration,perforation of the coating, etc., but would not be considered to be asignificant deviation from the non-coated composition.

Also disclosed are methods of treating a patient in need of colchicinetherapy with a colchicine solid complex. The colchicine solid complexesdisclosed herein and compositions prepared therefrom can be used inprevention or treatment of various diseases or conditions, including,for example, attacks of acute gouty arthritis and pain in attacks ofacute gouty arthritis, chronic gout (prophylaxis), a cystic disease, forexample polycystic kidney disease or cystic fibrosis, a lentiviralinfection, demyelinating diseases of central or peripheral origin,multiple sclerosis, cancer, an inflammatory disorder such as rheumatoidarthritis, glaucoma, Dupuytren's contracture, idiopathic pulmonaryfibrosis, primary amyloidosis, recurrent pericarditis, acutepericarditis, asthma, postpericardiotomy syndrome, proliferativevitreoretinopathy, Behçet's disease, Familial Mediterranean fever,idiopathic thrombocytopenic purpura, primary biliary cirrhosis, andpyoderma gangrenosum, or in enhancing bone formation or bone mineraldensity.

The following examples further illustrate the invention but, of course,should not be construed as in any way limiting its scope.

EXAMPLES

The following experimental procedures are used unless stated otherwise.

X-Ray Powder Diffraction (XRPD) analyses are performed on a PANalyticalX'Pert Pro diffractometer. The specimen is analyzed using Cu radiationproduced using an Optix long fine-focus source. An elliptically gradedmultilayer mirror is used to focus the Cu Kα X-rays of the sourcethrough the specimen and onto the detector. The specimen is sandwichedbetween 3-micron thick films, analyzed in transmission geometry, androtated to optimize orientation statistics. A beam-stop and helium purgeare used to minimize the background generated by air scattering. Sollerslits are used for the incident and diffracted beams to minimize axialdivergence. Diffraction patterns are collected using a scanningposition-sensitive detector (X'Celerator) located 240 mm from thespecimen. Prior to the analysis a silicon specimen (NIST standardreference material 640c) was analyzed to verify the position of thesilicon 111 peak. Peak lists were generated with PatternMatch 2.3.6.

Differential scanning calorimetry (DSC) analysis is carried out on a TAInstruments differential scanning calorimeter 2920; calibrated usingindium reference. The sample is placed in a standard aluminum DSC panwith an uncrimped lid. The sample cell is equilibrated at 25° C. andheated under nitrogen purge at a rate of 10° C./minute up to a finaltemperature of 350° C.

Thermogravimetry (TG) analyses are carried out on a TA Instruments 2950thermogravimetric analyzer. The calibration standards are nickel andAlumel™. Each sample is place in an aluminum sample pan and insertedinto the TG furnace. Samples are started at ambient and then heatedunder a stream of nitrogen at a heating rate of 10° C./min, up to afinal temperature of 350° C.

Fourier Transform Raman (FT-Raman) spectra are obtained using a FT-Raman960 spectrometer (Thermo Nicolet) using an excitation wavelength of 1064nm. Approximately 0.3 W or 0.5 W of Nd:YVO₄ laser power is used toirradiate the sample. The Raman spectra are measured with a germanium(Ge) detector. The samples are prepared for analysis by placing thematerial in a glass tube and positioning the tube in a gold-coated tubeholder in the accessory. A total of 256 sample scans are collected from3600-100 cm⁻¹ at a spectral resolution of 4 cm⁻¹, using Happ-Genzelapodization. Wavelength calibration is performed using sulfur. Data areanalyzed and peak lists are generated by using Omnic v. 7.2 software.

Hot stage microscopy is performed using a Linkam hot stage (model FTIR600) mounted on a Leica DM LP microscope. Samples are observed using a20× objective (obj.) with cross polarizers (CP) and lambda (λ)compensator. Samples are placed on a coverslip. A second coverslip isthen placed over the sample. Each sample is visually observed as thestage is heated. Images are captured using a SPOT Insight™ color digitalcamera with SPOT Software v. 4.5.9. The hot stage is calibrated usingUSP melting point standards.

Dynamic vapor sorption/desorption (DVS) data are collected on a VTISGA-100 Vapor Sorption Analyzer over a range of 5% to 95% relativehumidity (RH) at 10% RH intervals under a nitrogen purge. Samples ae notdried prior to analysis. Equilibrium criteria used for analysis wereless than 0.0100% weight change in 5 minutes, with a maximumequilibration time of 3 hours if the weight criterion was not met. Dataare not corrected for the initial moisture content of the samples.Sodium chloride and polyvinypyrrolidine are used as calibrationstandards.

Example 1 Preparation of Colchicine Malic Acid Solid Complex: Co-Crystal

Colchicine malic acid co-crystal is prepared by a slurry experimentusing ethyl acetate. Approximately 143 mg of colchicine and 146 mg ofL-malic acid are placed into 5 mL of ethyl acetate. The mixture is leftto slurry for one day. Excess ethyl acetate is then decanted and thesolid is washed with approximately 10 mL of diethyl ether. The solidco-crystal is isolated by vacuum filtration. The isolated solids areanalyzed using XRPD, FT-Raman, DSC, TGA, DVS, and ¹H-NMR. Theacid/colchicine ratio is approximately 1:1, and the material appears tobe unsolvated.

The ¹H-NMR spectrum is consistent with an unsolvated 1:1 malic acidcocrystal.

XRPD pattern of colchicine malic acid co-crystal is provided in FIG. 1and a peak listing is provided in Table 1 below.

TABLE 1 Position (°2θ) I/I_(o) 6.0 14.75 7.2 100.00 8.5 16.63 11.1 28.6012.0 15.73 13.1 66.83 13.4 20.46 14.0 12.10 14.4 15.09 16.3 42.47 16.737.47 16.9 21.98 17.7 16.60 18.4 51.14 19.0 10.28 19.9 27.99 20.6 16.7022.0 64.35 23.3 26.34 23.6 27.18 24.1 14.31 24.6 47.95 26.3 12.84 26.814.25 27.6 19.69 27.9 14.21 28.9 13.44 29.4 15.66

The DSC curve of colchicine malic acid co-crystal exhibits an endothermwith an onset temperature at approximately 66° C. This event isconfirmed by hotstage analysis as the melt. The TG curve exhibits aweight loss of approximately 2.8% up to 75° C., suggesting the materialcontains residual solvent.

The DVS data suggests the material is hygroscopic. The material exhibitsa weight loss of approximately 1.5% upon equilibration at 5% RH,consistent with the thermal data above. A weight gain of approximately22% is observed on the sorption step with no hysteresis upon desorption.Equilibrium weight is not achieved above 75% RH, indicating that higherweight gains may be possible.

A summary of the DSC, TG, Hotstage, DVS and ¹H-NMR studies are providedin Table 2.

TABLE 2 Analytical Technique Results DSC Endo 70° C. TG 2.8% weight lossup to 75° C. Hotstage 24.6: birefringent with extinction 68.3: — 79.6:losing birefringence 82.0: melting 84.6: — 93.9: — 103.4: liquid flow129.5: — 213.0: no decomposition observed DVS Sorption: 1.5% weight lossupon equilibration at 5% RH 6.2% weight gain from 5 to 75% RH 15.6%weight gain from 75 to 95% RH Desorption: 15.0% weight loss from 95 to75% RH 9.6% weight loss from 75 to 5% RH Post DVS XRPD Colchicine malicacid co-crystal ¹H-NMR (MeOD) Consistent with a 1:1 co-crystal

The Raman spectrum of colchicine malic acid co-crystal is shown in FIG.2. The peak list is given in Table 3 below.

TABLE 3 Position in Wavenumbers (cm⁻¹) 420 1054 448 1101 482 1151 5211182 562 1215 594 1269 646 1287 681 1324 701 1350 723 1368 743 1402 7851444 793 1500 829 1566 864 1595 905 1732 920 2586 960 2844 1003 29351021 3179

The physical stability of colchicine malic acid co-crystal at 40° C./75%RH was investigated. The sample exhibits a net weight gain ofapproximately 5.4% after 4 days. The stressed sample is analyzed by XRPDand remains unchanged.

Example 2 Preparation of Colchicine Malic Acid Solid Complex: SingleCrystal Study

Colchicine malic acid cocrystal is prepared by vapor diffusion ofhexanes into an ethyl acetate solution containing equimolar amounts offree colchicine and L-malic acid. A 922 μL aliquot of an ethyl acetatestock solution of colchicine (217 mg, colchicine in 1000 μL) is combinedwith L-malic acid (122 μL) resulting in a clear solution. The vial isplaced, uncapped, in a chamber containing approximately 3 mL hexanes.The chamber is sealed to allow for vapor diffusion. Crystals ofcolchicine malic acid co-crystal are obtained.

A piece of colchicine malic acid co-crystal having approximatedimensions of 0.44×0.40×0.33 mm, is mounted on a glass fiber in randomorientation. Preliminary examination and data collection are performedwith Mo K_(α) radiation (λ=0.71073 Å) on a Nonius KappaCCDdiffractometer equipped with a graphite crystal, incident beammonochromator. Refinements are performed on an LINUX PC using SHELX.Cell constants and an orientation matrix for data collection areobtained from least-squares refinement using the setting angles of 12537reflections in the range 3°<θ<27°. The refined mosaicity fromDenzo/Scalepack is 0.52° indicating moderate crystal quality. The spacegroup is determined by the program XPREP. From the systematic presenceof the following conditions: hkl h+k+l=2n 00l l=4n, and from subsequentleast-squares refinement, the space group is determined to be I 4₁ (no.80). The data are collected to a maximum 2θ value of 54.95%, at atemperature of 150±1 K.

The tetragonal cell parameters and calculated volume are: a=20.7499(11),Å, b=20.7499(11), Å, c=15.2460(9), Å, α=90.00°, β=90.00°, γ=90.00°,V=6564.3(6) Å³. The structure is determined to be an anhydrous crystalform of the malic acid co-crystal. The crystal structure is comprised ofa three dimensional arrangement of colchicine molecules packed aroundcolumns of malic acid.

Example 3 Preparation of Colchicine Oxalic Acid Solid Complex:Co-Crystal

Colchicine oxalic acid co-crystal is prepared by either a cooling orambient solution experiment involving acetonitrile and ether.Approximately 173 mg of colchicine and 38.8 mg of oxalic acid are placedinto a solvent mixture containing approximately 2 mL of acetonitrile and16 mL of diethyl ether. The material is left to crystallize in solutionat room temperature. After 4 days, a solid is isolated by decanting theexcess solvents. The oxalic acid co-crystal is isolated with anacid/colchicine ratio of 1:2. It appears to be unsolvated. The isolatedsolids are analyzed using XRPD, FT-Raman, DSC, TGA, DVS, and ¹H-NMR.

XRPD pattern of colchicine oxalic acid co-crystal is provided in FIG. 3and a peak listing is provided in Table 4 below.

TABLE 4 Position (°2θ) I/I_(o) 7.4 100.00 9.2 33.15 9.4 19.56 10.8 27.6312.0 60.32 12.3 97.28 14.4 51.26 15.5 11.94 15.9 43.71 17.5 20.16 17.899.70 18.1 20.18 18.5 11.15 18.9 25.19 19.9 13.81 20.5 63.96 21.7 15.2622.0 16.93 22.6 14.36 23.7 66.76 24.1 27.44 24.8 11.28 25.5 29.56 26.126.93 28.9 11.69 29.8 15.45

The DSC curve of colchicine oxalic acid co-crystal exhibits an endothermwith an onset temperature at approximately 131° C. This endotherm isconfirmed as the melt by hotstage microscopy. Observed erraticendotherms above approximately 150° C. are indicative of decomposition.The TG curve exhibits a weight loss of approximately 1.7% up to 120° C.,suggesting the material contains residual solvent (also observed by¹H-NMR).

The DVS data suggests the material is hygroscopic. The material exhibitsa small weight loss of approximately 0.1% upon equilibration at 5% RH.The majority of the weight gain (˜13%) during the sorption step isobserved above 75% RH. Equilibrium weight is not achieved, indicatingthat higher weight gains may be possible. Significant hysteresis isobserved upon desorption and the material deliquesces.

The ¹H-NMR spectrum indicates that the structure of colchicine isintact. The stoichiometry of the acid/colchicine cannot be determineddue to the absence of detectable protons in oxalic acid; however,elemental analysis indicates that the material has a ratio of 1:2acid/colchicine.

A summary of the DSC, TG, Hotstage, DVS, ¹H-NMR, and elemental analysisstudies are provided in Table 5.

TABLE 5 Analytical Technique Results DSC Endo 144° C. TG 1.7% weightloss up to 120° C. Hotstage 26.9: birefringence with extinction 100.0:no changes 115.5: loss of birefringence, solid to liquid transition118.5: continuing 121.2: continuing 126.0: continuing 131.4: continuing135.5: slow flowing liquids 146.1: end of solid to liquid transition DVSSorption: 0.1% weight loss upon equilibration at 5% RH 0.5% weight gainfrom 5 to 75% RH 12.9% weight gain from 75 to 95% RH Desorption: 15.2%weight loss from 95 to 5% RH ¹H-NMR (MeOD) Consistent with structure offreebase Elemental (non-GMP) Consistent with 1:2 acid:colchicinecocrystal Theoretical: C: 62.15%, H: 5.90%, N: 3.15% Measured: C:62.07%, H: 6.15%, N: 3.28%

The Raman spectrum of colchicine oxalic acid co-crystal is shown in FIG.4. The peak list is given in Table 6 below.

TABLE 6 Position in Wavenumbers (cm⁻¹) 416 1148 443 1187 489 1198 5151213 540 1247 563 1269 594 1287 615 1325 645 1350 674 1381 685 1401 7001436 721 1505 744 1549 782 1592 797 1751 827 2252 861 2583 930 2842 9642866 992 2934 1020 2998 1053 3045 1099 3242

The physical stability of colchicine oxalic acid co-crystal at 40°C./75% RH is investigated. The sample exhibits a net weight loss ofapproximately 6.7% after 4 days. The resulting sample is colchicineoxalic acid co-crystal, but minor disorder and shifting of the peaks isobserved.

Example 4 Preparation of Colchicine Oxalic Acid Solid Complex:Co-Crystal, Tetrahydrofuran Solvate

Colchicine oxalic acid co-crystal hemi-tetrahydrofuran solvate isisolated with an acid/colchicine ratio of 1:2. The material is preparedfrom an ambient solution experiment involving THF and hexanes.

The ¹H-NMR spectrum indicates that the structure of colchicine isintact. The stoichiometry of the acid/colchicine cannot be determineddue to the absence of detectable protons in oxalic acid. Elementalanalysis (non-cGMP) indicates that the material has a ratio of 1:2acid/colchicine and is also consistent with a hemi THF solvate. Asummary of the ¹H-NMR and elemental analyses is provided in Table 7below.

TABLE 7 Analytical Technique Results ¹H-NMR (MeOD) Consistent withstructure, ~0.4 moles THF Elemental (non-GMP) Consistent with 1:2:1acid/colchicine/ THF solvated cocrystal Theoretical: C: 62.75%, H:5.90%, N: 2.93% Measured: C: 62.64%, H: 6.36%, N: 2.91%

An XRPD pattern of colchicine oxalic acid co-crystal tetrahydrofuransolvate is provided in FIG. 5.

Example 5 Preparation of Colchicine Para-Toluenesulfonic Acid SolidComplex: Co-Crystal

Colchicine para-toluenesulfonic acid co-crystal is prepared from anambient solution experiment involving THF and hexanes. Approximately 149mg of colchicine and 70.9 mg of para-toluenesulfonic acid are placedinto a solvent mixture containing approximately 5.6 mL oftetrahydrofuran and 1 mL of hexanes. The material is left to crystallizein solution at room temperature. After 1 day, colchicinepara-toluenesulfonic acid co-crystal is isolated by vacuum filtration.The isolated solids are analyzed using XRPD, FT-Raman, DSC, TGA, DVS,and ¹H-NMR. The acid/colchicine ratio is approximately 1:1, and thematerial appears to be unsolvated.

XRPD pattern of colchicine para-toluenesulfonic acid co-crystal isprovided in FIG. 6 and a peak listing is provided in Table 8 below.

TABLE 8 Position (°2θ) I/I_(o) 6.6 31.47 6.8 21.42 9.6 12.95 12.8 100.0013.7 10.84 14.3 29.56 14.8 10.18 15.1 33.41 15.4 16.87 17.1 33.81 17.512.59 18.6 37.46 20.9 10.02 22.2 27.41 22.7 33.44 23.7 29.95 23.9 25.3026.4 27.02

The DSC curve exhibits an endotherm with an onset temperature atapproximately 198° C. Hotstage microscopy confirms this event as themelt, which occurs concurrently with decomposition. The TG curveexhibits a negligible weight loss of approximately 0.4% up to 175° C.,suggesting the material is not solvated.

The DVS data suggests the material is not significantly hygroscopic. Aweight gain of ˜0.4% is observed during the sorption step. The materialdesorps slightly more weight upon desorption than was gained, with a netweight loss of 0.01%. The resulting sample is colchicinepara-toluenesulfonic acid co-crystal by XRPD.

The ¹H-NMR spectrum is consistent with an unsolvated 1:1para-toluenesulfonic acid cocrystal.

A summary of the DSC, TG, Hotstage, DVS, ¹H-NMR, and elemental analysisstudies are provided in Table 9.

TABLE 9 Analytical Technique Results DSC Endo 198° C. TG 0.4% weightloss up to 175° C. Hotstage 25.3: birefringent with extinction 100.0: nochange 175.0: no change 190.8: solid/liquid transition beginning 196.7:solid/liquid transition done, decomposition observed 32.4: norecrystallization DVS Sorption: 0.01% weight loss upon equilibration at5% RH 0.4% weight gain from 5 to 95% RH Desorption: 0.5% weight lossfrom 95 to 5% RH Post DVS XRPD Colchicine toluenesulfonic acidco-crystal ¹H-NMR (MeOD) Consistent with a 1:1 cocrystal

The Raman spectrum of colchicine para-toluenesulfonic acid co-crystal isshown in FIG. 7. The peak list is given in Table 10 below.

TABLE 10 Position in Wavenumbers (cm⁻¹) 441 987 459 1003 482 1019 5061032 522 1053 535 1083 555 1095 580 1120 600 1148 618 1159 638 1177 6641186 677 1213 703 1241 716 1273 728 1285 751 1301 785 1322 803 1349 8331389 853 1441 863 1468 914 1494 949 1516

The physical stability of colchicine para-toluenesulfonic acidco-crystal at 40° C./75% RH is investigated. The sample exhibits a netweight gain of approximately 1.0% after 4 days. The resulting sample isanalyzed by XRPD and is unchanged.

The terms “comprising”, “having”, “including”, and “containing” are tobe construed as open-ended terms (i.e., meaning “including, but notlimited to”). The terms “a” and “an” do not denote a limitation ofquantity, but rather denote the presence of at least one of thereferenced item. The term “or” means “and/or”. The endpoints of allranges directed to the same component or property are inclusive andindependently combinable.

Unless defined otherwise, technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart to which this invention belongs.

Embodiments of this invention are described herein, including the bestmode known to the inventors for carrying out the invention. Variationsof those preferred embodiments may become apparent to those of ordinaryskill in the art upon reading the foregoing description. The inventorsexpect skilled artisans to employ such variations as appropriate, andthe inventors intend for the invention to be practiced otherwise than asspecifically described herein. Accordingly, this invention includes allmodifications and equivalents of the subject matter recited in theclaims appended hereto as permitted by applicable law. Moreover, anycombination of the above-described elements in all possible variationsthereof is encompassed by the invention unless otherwise indicatedherein or otherwise clearly contradicted by context.

1. A solid complex, comprising: colchicine and a guest, wherein theguest is malic acid, oxalic acid, or para-toluenesulfonic acid; andwherein the solid complex comprising colchicine and malic acid comprisesa colchicine malic acid co-crystal comprising XRPD peak positions at6.0, 7.2, 8.5, 11.1, 13.1, 16.3, 16.7, 18.4, 19.9, 22.0, and 24.6±0.2degrees 2-theta; wherein the solid complex comprising colchicine andoxalic acid comprises a colchicine oxalic acid co-crystal comprisingXRPD peak positions at 7.4, 9.2, 9.4, 10.8, 12.0, 12.3, 14.4, 15.9,17.8, 18.9, 20.5, and 23.7±0.2 degrees 2-theta or an XRPD patterncomprising the peaks of FIG. 5; and wherein the solid complex comprisingcolchicine and para-toluenesulfonic acid comprises a colchicinepara-toluenesulfonic acid co-crystal comprising XRPD peak positions at6.6, 6.8, 9.6, 12.8, 14.3, 15.1, 17.1, 18.6, and 22.7±0.2 degrees2-theta.
 2. The solid complex of claim 1, wherein the solid complex iscolchicine malic acid co-crystal comprising one or more of thefollowing: XRPD peak positions listed in Table 1; an XRPD patterncomprising the peaks of FIG. 1; FT-Raman peaks at 2935, 1595, 1500,1444, 1350, 1324, and 1287±4 cm⁻¹; FT-Raman peaks listed in Table 3;FT-Raman spectrum comprising the peaks of FIG. 2; an endotherm peak ofabout 70° C. by differential scanning calorimetry analysis; or a ratioof about 1:1 malic acid:colchicine.
 3. The solid complex of claim 1,wherein the solid complex is colchicine oxalic acid co-crystalcomprising one or more of the following: XRPD peak positions listed inTable 4; an XRPD pattern comprising the peaks of FIG. 3; FT-Raman peaksat 2934, 1592, 1549, 1505, 1436,and 1401±4 cm⁻¹; FT-Raman peaks listedin Table 6; FT-Raman spectrum comprising the peaks of FIG. 4; anendotherm peak of about 144° C. by differential scanning calorimetryanalysis; or a ratio of about 1:2 oxalic acid:colchicine.
 4. The solidcomplex of claim 1, wherein the solid complex is colchicine oxalic acidco-crystal tetrahydrofuran solvate comprising a ratio of about 1:2:1oxalic acid:colchicine:tetrahydrofuran.
 5. The solid complex of claim 1,wherein the solid complex is colchicine para-toluenesulfonic acidco-crystal comprising one or more of the following: XRPD peak positionslisted in Table 8; an XRPD pattern comprising the peaks of FIG. 6;FT-Raman peaks at 1516, 1468, and 1322±4 cm⁻¹; FT-Raman peaks listed inTable 10; FT-Raman spectrum comprising the peaks of FIG. 7; an endothermpeak of about 198° C. by differential scanning calorimetry analysis; ora ratio of about 1:1 para-toluenesulfonic acid:colchicine.
 6. Acomposition, comprising: a solid complex comprising colchicine and aguest, wherein the guest is malic acid, oxalic acid orpara-toluenesulfonic acid according to claim 1; and a pharmaceuticallyacceptable excipient.
 7. The composition of claim 6, wherein thecomposition is a solid oral dosage formulation.